This invention relates to the steering of a land vehicle and particularly relates to those four-post vehicles which are steered by a combination of turning the tracks or wheels of the machines and of driving those tracks or wheels at differential speeds.
Steering control systems, particularly automatic steering control systems as in U.S. Pat. No. 3,848,690, for land vehicles are known in the prior art. Moreover, U.S. Pat. No. 3,917,015 shows a system for steering a vehicle by turning the tracks or wheels of the vehicle and operating the tracks or wheels on the right side at a different speed than those on the left side. However, none of the systems known in the art relieve the distortion on the frame caused by the steering of the vehicle. Although U.S. Pat. No. 3,857,577 shows a system for measuring or sensing frame distortion for controlling the slope of the working member of the machine, it has not been suggested that the distortion on the frame of the machine can be relieved or minimized by sensing that distortion and making the proper adjustments in the steering control system.